Adjustable oral devices for preventing or reducing snoring or obstructive sleep apnea (OSA)

ABSTRACT

A device (10) having a body (12) formed from as a one-piece single unit having a first tray portion (16) for receiving the upper dental arch of the oral cavity of the wearer and a second tray portion (14) for receiving the lower dental arch of the oral cavity of the wearer. Integrally formed therewith and connecting the two tray portions are two connecting portions (18), (20) which are flexible and the two tray sections are of a design or material or combination of design and material selected to achieve retention of the trays on the teeth of a user.

The present invention relates to oral devices for preventing or reducingsnoring and/or Obstructive Sleep Apnea (OSA), kits of parts and a methodof assembling mandibular advancement devices.

Snoring and OSA are associated conditions with heavy snoring being acommon indicator of the presence of OSA. Snoring is caused by airturbulence resulting from the vibration or disruption of the tissue andstructure of the upper airway. Such disruption of the tissue andstructure of the airway may extend to the point of causing multipleevents of closure or obstruction of the upper airway characteristic ofOSA.

Snoring is often a source of sleep disruption to the bed partner of thesnorer resulting in impairment of sleep and relationship. In the longterm snoring, even when not immediately associated with the presence ofOSA, may cause inflammation, swelling and damage to the tissue of theupper airway that may in turn encourage the development of OSA.Reduction in snoring is of benefit to both the sufferer and the bedpartner and where that snoring is a precursor or indicator of OSA thereis an imperative to seek treatment.

There are various alternative treatments offered to manage the snoringcondition with various evidence of success. Most pharmacy products seekto address the condition of mucosal tissue. There is limited evidence asto the effectiveness of such products. The only treatment to reducesnoring that currently has widespread acceptance of a high degree orlikelihood of effectiveness is oral device therapy. Oral devices with amechanism for mandibular advancement act on the muscles supporting theairway and physically sustain airway patency.

Additionally, oral devices have emerged as an alternative to continuouspositive airway pressure (CPAP) for OSA. There is a strong evidence basedemonstrating that oral devices improve OSA in the majority of patients,particularly those with mild to moderate OSA but also some suffererswith severe OSA. Oral devices are generally well tolerated, althoughshort-term adverse effects during acclimatization are common. Long-termdental changes may occur, but these are for the most part subclinicaland do not preclude continued use. Patients often prefer oral device useto gold-standard CPAP treatment. Although most head-to-head trialsconfirm CPAP as superior in reducing OSA parameters on polysomnographythis greater efficacy does not necessarily translate into better healthoutcomes in clinical practice. Comparable effectiveness of oral devicesand CPAP has been attributed to higher user compliance and acceptance oforal device use as compared with CPAP use.

Oral devices fall broadly into either of two categories. Firstly thereare custom devices specific to the patient based on taking a physicalimpression of the patient's teeth or more recently from a digital scanimage of the teeth. Such oral devices generally offer good levels ofcomfort and retention on the teeth. However they are expensive and thatexpense may prove inadvisable if the patient discovers that they areunable to tolerate overnight wearing of the device or they are one ofthe approximately 15% of patients for whom an oral device is noteffective.

Thermo-formable devices, generally known as boil-and-bite, are a muchless expensive alternative to custom devices and offer a sensible routeto first purchase and for many people may become the only device theyrequire.

Although there is a plethora of oral device designs most share a commondesign strategy of advancing the lower jaw or mandible. Custom devicesand boil-and-bite devices often share this same design feature andmechanism of action. Studies comparing the effectiveness of customdevices with boil-and-bite devices have generally concluded that customdevices are more effective. However the detail of these studiesfrequently indicate that the higher degree of effectiveness of customdevices is not down to any superior mechanism of action but primarilydown to greater retention on the teeth.

With oral devices, advancing the mandible is generally achieved bypositioning the lower tray, sometimes called the lower portion, forwardof the neutral position vis-à-vis forward of the upper tray or upperportion. This is usually achieved by some form of connection between theupper and lower tray which fixes the lower tray or portion in a forwardposition so that when the device is placed in the oral cavity the lowerteeth sit forward of the natural bite position of the wearer.

Better designs of oral devices have a means of varying the extent of theadvancement of the lower tray. This is important, firstly because thenatural bite position varies from person to person and secondly becausethe degree of advancement necessary to treat the snoring or OSA variesfrom individual to individual and even varies in the same individualover time.

Designs with a variable advancement mechanism broadly fall into threecategories; those where the mechanism is located at the side of thedevice, those where the mechanism is located at the front of the device,those where the mechanism is located towards the rear of the device.

An example of a device design where the mechanism is located at the sideof the device is disclosed by U.S. Pat. No. 6,109,265 and marketed asthe Myerson EMA. The advantage of such designs is that as well asachieving mandibular advancement they allow the jaw to move relativelyfreely in an upwards/downwards direction, sometimes referred to asmovement in the sagittal plane. The disadvantages of such designs arefirstly that the majority of them achieve mandibular advancement throughthe use of linkage rods or straps. These are of fixed length and varyingthe amount of mandibular advance is usually achieved by replacing rodsor straps of one length with those of a different length. Unless welldesigned the rods or straps and particularly the connection points canprotrude into the cheek wall causing discomfort and even inflammation.The second disadvantage of these designs is that because the rods orstraps are located in parallel down each side of the device theyrestrict the ability of the jaw to move from side to side, sometimesreferred to as movement in the transverse plane.

An example of a device design where the advancement mechanism is locatedat the front of the device is disclosed by U.S. Pat. No. 5,868,138,other devices include the TAP 3 device.

Such a design will achieve mandibular advancement and may allow for amechanism that is less bulky than a mechanism located at the side of thedevice and the mechanism generally will not protrude into the cheek wallcausing discomfort and inflammation. The first disadvantage of such adesign is that it will not permit the jaw to move upwards or downwards,through the sagittal plane. The second disadvantage is that althoughsuch devices allow for side-to-side movement of the device in thetransverse plane the pivot point of the device will be at the frontwhereas the mandible pivots at the back of the oral cavity so the deviceis not sympathetic to the movement of the jaw

An example of a device design where the advancement mechanism is locatedat the close to the rear of the device is the Apnea RX device.

Such a design will achieve mandibular advancement and may allow for amechanism that is less bulky and the mechanism generally will notprotrude into the cheek wall causing discomfort and inflammation. Thefirst disadvantage of such a design is that it will only permit at bestlimited and at worst no movement upwards or downwards of the jaw,through the sagittal plane. The second disadvantage of such a design isthat it will only permit at best limited and at worst no movementside-to-side of the jaw, through the transverse plane.

A departure from designs that position the lower tray forward of theneutral position vis-à-vis the upper tray by some form of connectionbetween the upper and lower tray is disclosed by U.S. application Ser.No. 14/308,636 (Ingemarsson-Matzen) In this design there is a fixedposition resilient hinge located at the rear (mid-way point) of thedevice. Advancement of the jaw is achieved by either a mechanism locatedsolely on the upper tray to reduce the distance between the front apexof the upper tray and the fixed position resilient hinge (decrease thelength of the upper tray) or a mechanism located solely on the lowertray to increase the distance between the front apex of the lower trayand the fixed position resilient hinge (increase the length of the lowertray) A key component of this design is a resilient hinge of sufficientrobustness to be capable of resisting the force exerted by the musclesof the jaw seeking to return the jaw to its natural bite position. Theadvantage of such a design is that it permits good upwards or downwardsmovement of the jaw, through the sagittal plane. The disadvantage ofsuch a design is that a resilient hinge will only permit at best verylimited and at worst no movement side-to-side of the jaw, through thetransverse plane.

A variation on the Ingemarsson-Matzen design is U.S. Pat. No. 7,810,502(Nguyen). This also features a fixed position hinge mechanism located atthe rear of the upper tray. The hinge comprises a tubular memberembedded in the upper tray and a wire running through the tubular memberand attached to the lower tray. Advancement of the jaw/mandible isachieved by mechanism located on the lower tray and acting on the wireand intended to increase the distance between the front apex of thelower tray and the fixed position tubular member part of the hinge(increase the length of the lower tray). As with the Ingemarsson-Matzendesign the advantage of the Nguyen design is that it permits goodupwards or downwards movement of the jaw, through the sagittal plane.The disadvantage of the design is that the tubular member hinge and wirewill only permit at best very limited and at worst no movementside-to-side of the jaw, through the transverse plane.

Any device that by its design limits natural movement of the jaw in anyplane will result in one of two or a combination of two undesirableeffects. Firstly the force exercised by the jaw seeking to move in adirection restricted by the design of the device will act to pull thedevice away from the teeth causing the device to fall loose.Alternatively the grip of the device on the teeth may be stronger thanthe force exercised by the jaw in which case the wearer will suffer anelement of discomfort. This may be sufficient over time to causetemporomandibular disorders (sometimes called TMD or TMJD) in somecases.

It will be appreciated that such devices which are of the boil and bitetype are more likely to be less close fitting and therefore simply fallout when such force is exercised by the jaw. Such devices which arecustom fitted are more likely to be tighter fitting and therefore morelikely to cause discomfort when such force is exercised and in the longterm possibly temporomandibular disorders.

It has also been noted that devices that achieve advancement by amechanism fixing the upper tray to the lower tray do not permitdesirable movement of the mandible vis-à-vis the maxilla in an up anddown or side to side direction. One alternative to devices that fix theupper tray to the lower tray are devices utilizing a resilient hinge.Such devices, however, are poor at allowing side to side movement.

In accordance with a first aspect of the present invention, there isprovided an oral device comprising a first tray portion for receiving atleast a portion of the upper dental arch of the oral cavity of a wearerand a second tray portion for receiving at least a portion of the lowerdental arch of the oral cavity of the wearer, the tray portions togetherwith or connected by flexible members or sections capable of assuming afolded configuration within the oral cavity wherein the first trayportion at least partially overlies the second tray portion, and whereinassociated with each flexible member or section is an adjustment methodcapable of operating or acting on or across the flexible member fordetermining the apex of the fold when the device is in its foldedconfiguration such that the location of the apex of the fold determinesthe relative position of the first tray portion with respect to thesecond tray portion in the folded configuration.

The present invention overcomes and/or addresses one or more of thelimitations of all the aforementioned designs in enabling movement bothin the sagittal and transverse planes whilst providing a simplemechanism for adjustment in the coronal plane. The present inventiontakes advantage of the fact that the jaw is itself a hinge and that aunitary device fitted to the upper and lower teeth will if the device issufficiently flexible fold round to adapt to the oral cavity. Thenatural fold or apex of the curve will be at the point determined by thefact that the device is fixed to the upper and lower teeth. For a personwith a neutral bite position the pivot point will be close to halfwayalong the overall length of the device.

Varying the location of the fold point by a mechanism proximate to andacting directly on or across each of the flexible members in the presentinvention will change the relative position of the tray portions to oneanother in use and therefore the relative positions of the mandible andmaxilla. By incorporating an adjustable mechanism or assembly proximalto the flexible portion and acting on or across each of them of thedevice a plurality of alternative fold points may be provided.

An advantage of an adjustment mechanism that can change the fold pointof the flexible members is that any change in the fold point has atwofold change in the advancement of the lower tray vis-a-vis the uppertray and consequently the advancement of the jaw/mandible. Thus each 1mm change in the fold position will effect a 2 mm change in theadvancement of the lower tray vis-a-vis the upper tray. This may, forexample, be contrasted with the Ingemarsson-Matzen and Nguyen designswhere a 1 mm increase of the distance between the front apex of thelower tray and the fixed position hinge results in only an overall 1 mmchange in the advancement of the lower tray vis-a-vis the upper tray. Asthe space to locate any adjustment mechanism and the size of suchmechanism is constrained by the small free areas between the device andthe teeth, cheeks and tongue the current invention allows for a greaterrange of jaw/mandible advancement for size of mechanism compared withother designs.

The ability to advance the mandible is a requirement of an effectiveoral device for treating snoring and sleep apnoea. The flexible membersor sections of the present invention not only permit movement in thesagittal plane but also permit lateral movement of the tray portionsrelative to one another greatly improving the comfort of a wearer whenthe device is used.

The device may comprise two flexible members one on each side of thedevice integrally formed with the tray portions.

The device may comprise alternative discrete flexible members. The useof a discrete flexible member permits the flexible member to be readilymade of an alternative material to that of the tray portion; a featureparticularly useful when the tray portion is formed from a dentalimpression to create a custom device.

The discrete members and the tray portions may have mating means so thatthe flexible members may mate with the first and second tray portions.

The mating members may comprise any one or more of the following: hookand loop, adhesive means, and tongue and groove.

Suitably, the mating members may be complementarily shaped with respectto one another. More suitably the flexible members may have male matingmeans disposed thereon and the tray portions have female mating meansdisposed thereon.

The device may have adjustment means comprising a support member mountedon a tray portion and an adjustable member moveably mounted on thesupport member such that the adjustment member is capable of adopting aplurality of configurations for determining a plurality of locations forthe apex of the fold when the device is in a folded configuration.

The adjustment member may be capable of translational movement withrespect to the support member. Suitably, the support member may comprisea lug.

The adjustment member may comprise a pin having a threaded shaft and arounded head against which the flexible member may abut in the foldedconfiguration. Suitably, the adjustment means may be mounted on thesecond tray portion.

The adjustment member may be mounted by means of adhesive, rivet and orover moulding or other known means of securing two materials together.Suitably, mounting is by means of overmoulding. The adjustment membermay have one or more flaps which will sit below the surface of trayportion which is overmoulded over the adjustment member.

The adjustment means is capable of dictating the maximum forward orrearward displacement of the first tray vis-à-vis the second tray andvice versa when the device is folded and in situ on the teeth.

The flexible member or portion may comprise or may be overlaid, inlaidor reinforced by a more robust and less malleable or other alternativematerial than the material used for the trays. The material may comprisepolyethylene terephthalate resins commonly known as PET or BOPET or asimilar material having an element of resilient spring return force.

The device may further comprise reinforcement means at the fold toprovide reinforcement. The reinforcement means may comprise aresiliently deformable member. The resiliently deformable member may bemanufactured from a material comprising any one or more of polyethyleneterephthalate resins commonly known as PET or BOPET or a similarmaterial. The resilient member may provide spring return force at thefold point which may help retain the device in situ in use by biasingthe first tray portion towards the maxilla as the resilient member willbias the device into its unfolded configuration.

In accordance with an aspect of the present invention there is providedan oral device comprising a first tray portion for receiving at least aportion of the upper dental arch of the oral cavity of a wearer and asecond tray portion for receiving at least a portion of the lower dentalarch of the oral cavity of the wearer, the tray portions together withor connected by flexible members or sections capable of assuming afolded configuration within the oral cavity wherein the first trayportion at least partially overlies the second tray portion, and whereinassociated with each flexible member or section is an adjustment meanscapable of contacting said flexible member for determining the apex ofthe fold when the device is in its folded configuration wherein thelocation of the apex of the fold determines the relative position of thefirst tray portion with respect to the second tray portion in the foldedconfiguration, and wherein at least a portion of at least one adjustmentmeans is capable of contact with the flexible members or sections whenin a folded configuration to determine the location of the apex of thefold.

In accordance with a further aspect of the present invention, there isprovided a kit of parts for mandibular advancement comprising an oraldevice as described hereinabove and a plurality of discrete flexiblemembers of varying lengths.

In accordance with a further aspect of the present invention, there isprovided a method of assembling an oral device as described hereinabovecomprising selecting a discrete flexible member of desired length andconnecting the first and second tray portion with said flexible member.

In accordance with an aspect of the present invention there is providedan oral device comprising a first tray portion for receiving at least aportion of the upper dental arch of the oral cavity of a wearer and asecond tray portion for receiving at least a portion of the lower dentalarch of the oral cavity of the wearer, the tray portions together withor connected by flexible members or sections having a foldedconfiguration wherein the first tray portion at least partially overliesthe second tray portion, and wherein associated with each flexiblemember or section is an adjustment means which contact the flexiblemember or section to determine the apex of the fold when the device isin its folded configuration such that the location of the apex of thefold determines the relative position of the first tray portion withrespect to the second tray portion.

The present invention will now be described, by way of example only,with reference to the accompanying drawings, in which:

FIG. 1 shows a device in accordance with the present invention; FIGS. 2aand b show the device of FIG. 1 folded;

FIGS. 3 a to c show the device of FIG. 1 folded and the advancement ofthe upper or lower tray relative to one another in accordance withdisplacement of the adjustment means;

FIGS. 4a to d show a device in accordance with the present invention indifferent configurations;

FIG. 5 shows a device in accordance with the present invention havingalternative adjustment means;

FIG. 6 shows a device in accordance with the present invention;

FIG. 7 shows a device in accordance with the present invention; and

FIG. 8 shows a device in accordance with the present invention.

FIG. 1 shows a device 10 having a body 12 formed from as a one-piecesingle unit having a first tray portion 16 for receiving the upperdental arch of the oral cavity of the wearer and a second tray portion14 for receiving the lower dental arch of the oral cavity of the wearer.Integrally formed therewith and connecting the two tray portions are twoconnecting portions 18, 20 which are flexible and the two tray sectionsare of a design or material or combination of design and materialselected to achieve retention of the trays on the teeth.

The first and second tray portion have a number of spaced apart indents22,24,26,27 and 22′24′26′27′ respectively which overlie one another whenthe device is folded and in a neutral position. The indents permit thetrays to flex and better conform to the shape of a wearer's upper andlower dental arch.

Disposed on a first surface 28 of the device, said surface 28 beingsubstantially planar, is a pair of adjustment assemblies 30, 32 eachhaving a lug 34 extending perpendicularly from a planar base 36 mountedon or partially into the first surface 28 of the device. Each lug 34 hasa threaded bore 38 which receives the free end 40 of a threaded shaft 41of an adjustment screw 42. At the other end of the threaded shaft is therounded head 44 of the adjustment screw 42 which has a series oflongitudinal ridges to provide grip when adjusting the distance betweenthe lug 34 and the rounded head 44. Adjusting the distance between thelug and rounded head in this way will dictate the point at which theconnectors will fold and as such the relative off set between the firsttray portion and the second tray portion in use.

FIGS. 2a and b show the device folded.

FIGS. 3 a to c show that that displacement of the adjustment mechanismhas a twofold change in the advancement of the lower tray vis-a-vis theupper tray and consequently the advancement of the jaw/mandible or viceversa. Thus each 1 mm change in the fold position will effect a 2 mmchange in the advancement of the lower tray vis-a-vis the upper tray orvice versa. As stated above, this may, for example, be contrasted withthe Ingemarsson-Matzen and Nguyen designs where a 1 mm increase of thedistance between the front apex of the lower tray and the fixed positionhinge results in only an overall 1 mm change in the advancement of thelower tray vis-a-vis the upper tray. As the space to locate anyadjustment mechanism and the size of such mechanism is constrained bythe small free areas between the device and the teeth, cheeks and tongueof the present invention may allow for a greater range of jaw/mandibleadvancement for size of mechanism compared with other designs, as setout in FIGS. 3 a to c.

FIGS. 4a to d show the device folded and the adjustment means dictatingthe location of the fold and thus the relative positions of the firstand second tray portions with respect to one another. Owing to theflexibility of the connecting portions, the adjustment means in factdictate the maximum displacement possible between the first and secondtray portions.

FIG. 4a shows the configuration where the first tray portion partiallyoverlies the second tray portion. The first tray portion is off-set bydistance ‘A’ from the second tray portion. Distance ‘A’ is dictated bythe co-operation between the adjustment screws 42 and the connectors18,20. The position of the adjustment means and in particular the head44 of the adjustment screw 42 will dictate where the fold of theconnectors 18, 20 will be when in use. The adjustment means is capableof dictating the maximum forward or rearward displacement of the firsttray vis-à-vis the second tray and vice versa when the device is foldedand in situ on the teeth. Depending upon the desired effect the maximumdisplacement of the relative positions of the mandible and maxilla maybe dictated by the adjustment means.

The arrow shows the direction of displacement of the tray portions withrespect to one another from a neutral position. This displacement caneither be rearward or forward from the neutral position.

The rounded head 44 of the adjustment screw 42 rests against the firstsurface 28 of the connectors 18, 20.

FIG. 4a shows the lower tray marginally displaced rearwards, distance A,from the upper tray portion

FIG. 4b shows a neutral position where there is no displacement of therelative positions of the upper or lower tray portions.

FIG. 4c shows the lower tray portion marginally displaced forwards,distance A′, from the upper tray portion.

FIG. 4d shows the lower tray portion further displaced forwards,distance A″, from the upper tray portion than that shown in FIG. 3 c.

Representative distances illustrated are A=4.5 mm (rearward); A′=3 mm(forward); and A″=6 mm (forward).

As previously stated, the present invention takes advantage of the factthat the jaw is itself a hinge and that a unitary device fitted to theupper and lower teeth will if the device is sufficiently flexible foldround to adapt to the oral cavity. In the absence of an adjustmentmechanism the natural fold or apex of the curve will be at the pointdetermined by the fact that the device is fixed to the upper and lowerteeth.

For a person with a neutral bite position the pivot point will be closeto halfway along the overall length of the device.

By including an adjustable mechanism or assembly proximal to theflexible portion of the device and capable of operating or acting on oracross each flexible member a plurality of fold points may be provided.Varying the location of the fold point will change the distance from theapex of the fold to the end point of the upper tray and the end point ofthe lower tray—increasing one of these distances and decreasing theother. Varying the fold point will also change the relative position ofthe tray portions to one another in use and therefore the relativepositions of the mandible and maxilla. The further back the adjustmentscrew is advanced away from the lug 34 and the first tray portion 14(which rests on the lower dental arch in use) the further forward themandible will be displaced relative to the maxilla when the device isworn. FIGS. 3a to c shows such displacement. This particular embodimentshows the mechanism having an adjustment screw but there are numerousalternative incremental or successive mechanisms known to the skilledperson that could be adapted to achieve the same objective of varyingthe fold point and which are encompassed in the scope of the presentinvention.

FIG. 5 shows one side of another embodiment having two reinforcementmembers 80 (only one shown) each associated with an adjustment assembly.The reinforcement members may have a resiliently deformable planar bodyconnected at one end 82 to the adjustment assembly. The free end 84 ofthe reinforcement member 80 lies over the flexible member or section andwhen the device is folded, the reinforcement member provides additionalresistance to folding thereby urging the upper tray into the maxilla tobetter assist in retaining the device in situ.

Alternatively the reinforcement member may be connected on both the topand bottom parts of the assembly. Alternatively the material may be toadd strength rather than resilience to the adjustment assembly.

The present invention provides an oral device of sufficient flexibilitythat it is capable of readily folding around a curve at any point over adistance of about 20 mm close to the mid-point of the device andsufficient strength that it will not deform or break down as it foldsaround a mechanism or assembly. Happily many materials are known in theart, examples include EVA, LDPE, TPU, SEBS, SEPS which are alreadyavailable and have such qualities and doubtless new materials will beadded to this group over time.

In another embodiment (FIG. 6), there is a device 100 whose principaldifference with the device 10 shown in FIGS. 1, 2 and 3 is that theintegrally formed flexible connectors 18, 20 are replaced with discreteflexible connectors 102, 104. The flexible connectors 102, 104 have asubstantially rectangular body with an upper surface 106 which liesflush with the first surface 128 of the device 100 in use.

The connectors have a substantially planar upper surface 106 and lowersurface 108. At either end of the connector 106, 108 are the firstmembers 110, 110′ of a mating pair. The second members 112, 112′ of themating pair is located on the first and second tray portions. The firstand second members comprise correspondingly shaped recess edges of theconnectors and tray portions such that when mated the upper surfaces ofthe connectors and tray portions are flush with one another and insubstantially the same plane, and the lower surfaces of the surfaces ofthe connectors and tray portions are flush with one another and insubstantially the same plane.

The tray portions are shown in FIG. 6 to have disposed on the recessededge a plurality of blind bores which are correspondingly shaped toreceive a plurality of protrusions disposed on the recessed edge of theconnectors. Other means envisaged by the skilled person by which theconnectors and the tray portions may mate are encompassed in the presentinvention, such as hook and loop mating, adhesive means, tongue andgroove, etc.

The length of the connectors can be varied in other embodiments suchthat the device is effective on any sized mandible and maxilla, and acustom fit for a user may be provided.

The material of the connectors can be varied from that of the trays tooptimize the comfort and strength of the respective parts as appropriateto their function.

In another embodiment (FIG. 7), there is a device 200 whose differencewith the device 10 shown in FIGS. 1 to 4 is that the connecting portions18, 20 are separate discrete flexible connectors 202, 204 upon which aremounted the adjustment assemblies 206, 208. The discrete connectors aremateable with the upper and lower tray portions 210,212 by means of maleand female mating members. The male mating members 214, 216 are disposedat either end of the discrete of the discrete connector 202, 204 and arecomplementarily shaped to the female mating members 218, 220 disposed onthe upper and lower tray portions respectively. The upper 222 and lowersurface 224 of the flexible connectors 202, 204 are flush with upper226, 228 and lower 230, 232 surfaces of the tray portions when thedevice is assembled.

In another embodiment (FIG. 8), there is a device 300 whose differencewith the device 10 shown in FIGS. 1 and 2 is the adjustment mechanism.The pair of adjustment assemblies 30, 32 are replaced by a linear track302 with asymmetrical teeth 304, and a stop 306 that engages the teeth304. The teeth are uniform but asymmetrical, with each tooth having amoderate ‘gentle’ slope on one edge and a much steeper slope on theother edge.

When the teeth are moving in the unrestricted (i.e., forward) direction,the stop easily slides up and over the gently sloped edges of the teeth,with a spring forcing it (often with an audible ‘click’) into thedepression between the teeth as it passes the tip of each tooth. Whenthe teeth move in the opposite (backward) direction, however, the pawlswill catch against the steeply sloped edge of the first tooth itencounters, thereby locking it against the tooth and preventing anyfurther movement in that direction.

The invention claimed is:
 1. An oral device comprising a first trayportion for receiving at least a portion of the upper dental arch of theoral cavity if a wearer, and a second tray portion for receiving atleast a portion of the lower dental arch of the oral cavity of thewearer, wherein the first and second tray portions together with orconnected by flexible members or sections capable of assuming a foldedconfiguration within the oral cavity wherein the first tray portion atleast partially overlies the second tray portion, wherein the flexiblemembers or sections is integrally formed with the first and second trayportions; and wherein associated with the flexible members or sectionsis an adjustment means comprising an adjustment assembly having a lugextending perpendicular from a lower surface of the first tray portion,or an upper surface of the second tray portion, a support member mountedon one of the first and second tray portions, and an adjustable membermoveably mounted on the support member; wherein the lug is furtherconfigured to capture a portion of a threaded shaft of the adjustablemember; and wherein a rounded head of the adjustable member directlycontacts the flexible members or sections at an apex of the flexiblemembers or sections when the oral device is in its folded configuration,such that an adjustment of the adjustable member determines a locationof the apex of the flexible members or sections at variance with thelocation that would otherwise be determined by the natural bite positionof the wearer, the location of the apex of the flexible members orsections determines a relative position of the first tray portion withrespect to the second tray portion.
 2. An oral device comprising a firsttray portion for receiving at least a portion of the upper dental archof the oral cavity of a wearer and a second tray portion for receivingat least a portion of the lower dental arch of the oral cavity of thewearer, the first and second tray portions connected by two foldableflexible members or sections wherein the flexible members or sections isintegrally formed with the first and second tray portions; and whereinassociated with each of the flexible members or sections is anadjustment means further comprising an adjustment assembly having a lugextending perpendicular from a lower surface of the first tray portion,or an upper surface of the second tray portion, a support member mountedon one of the first and second tray portions, and an adjustable membermove ably mounted on the support member; wherein the lug is furtherconfigured to capture a portion of a threaded shaft of the adjustablemember; wherein a rounded head of the adjustable member directlycontacts the flexible members or sections at an apex of the flexiblemembers or sections when the oral device is in a folded configuration,such that an adjustment of the adjustable member determines a locationof the apex of the flexible members or sections at variance with thelocation that would otherwise be determined by the natural bite positionof the wearer, the location of the apex of the flexible members orsections determines a relative position of the first tray portion withrespect to the second tray portion.
 3. The oral device of claim 1,wherein a number of the flexible members or sections is two, and whereinthe two flexible members or sections are discrete.
 4. The oral device ofclaim 3, wherein the flexible members or sections, and the first andsecond tray portions have mating means so that the flexible members orsections may mate with the first and second tray portions.
 5. The oraldevice of claim 4, wherein the mating members are complementarily shapedwith respect to one another.
 6. The oral device of claim 4, wherein themating members comprise any one or more of the following: hook and loop,adhesive means, and tongue and groove.
 7. The oral device of claim 4,wherein the flexible members or sections have male mating means disposedthereon and the first and second tray portions have female mating meansdisposed thereon.
 8. The oral device of claim 2, wherein the adjustablemember is capable of translational movement with respect to the supportmember.
 9. The oral device of claim 2, wherein the support membercomprises the lug.
 10. The oral device of claim 2, wherein theadjustment means is mounted on the second tray portion.
 11. The oraldevice of claim 1, wherein the adjustment means is mounted on theflexible members or sections such that the adjustable member is capableof adopting a plurality of configurations for directly contacting theapex and determining a plurality of locations for the apex of theflexible members or sections when the oral device is in a foldedconfiguration.
 12. The oral device of claim 1, wherein the adjustmentmeans is mounted partly on the flexible members or sections and partlyon the first and second tray portions such that the adjustable member iscapable of adopting a plurality of configurations for directlycontacting the apex and determining a plurality of locations for theapex of the flexible members or sections when the oral device is in afolded configuration.
 13. The oral device of claim 1, wherein theflexible members or sections comprises a material less malleable thanthe first and second tray portions.
 14. The oral device of claim 1,wherein the flexible members or sections comprises a first and secondmaterial where the second material is less malleable than the first andsecond tray portions and the second material is overlaid on the firstmaterial of the flexible members or sections.
 15. The oral device ofclaim 1, further comprising biasing means for biasing the oral deviceinto an unfolded configuration.
 16. The oral device of claim 15, whereinthe biasing means comprises one or more resilient members disposedproximal to the flexible members or sections.
 17. The oral device ofclaim 16, wherein the one or more resilient members overlie the flexiblemembers or sections.
 18. The oral device of claim 16, wherein the one ormore resilient members are integrally formed with the flexible membersor sections.
 19. The oral device of claim 15, wherein the biasing meanscomprises any one or more of the following: polyethylene terephthalateresins commonly known as PET or BOPET or a similar material.
 20. Theoral device of claim 19, wherein the biasing means is connected to theadjustment means.
 21. A kit of parts for mandibular advancementcomprising the oral device of claim 20 and a plurality of discreteflexible members of varying lengths.
 22. A method of assembling the oraldevice of claim 1, comprising selecting a discrete flexible member of adesired length and connecting the first and second tray portions withsaid discrete flexible member.